import org.apache.storm.kafka.bolt.mapper.FieldNameBasedTupleToKafkaMapper; //导入依赖的package包/类
/**
 * Creates Kafka bolt.
 *
 * @param topic Kafka topic
 * @return {@link KafkaBolt}
 */
protected KafkaBolt createKafkaBolt(final String topic) {
    return new KafkaBolt<String, String>()
            .withProducerProperties(kafkaProperties)
            .withTopicSelector(new DefaultTopicSelector(topic))
            .withTupleToKafkaMapper(new FieldNameBasedTupleToKafkaMapper<>());
}
 

import org.apache.storm.kafka.bolt.mapper.FieldNameBasedTupleToKafkaMapper; //导入依赖的package包/类
/**
 * Constructor.
 * @param topic The topic to produce to.
 */
@SuppressWarnings("unchecked")
public KafkaProducer(String topic, Properties properties) {
  this();
  withTopicSelector(new DefaultTopicSelector(topic));
  withTupleToKafkaMapper(new FieldNameBasedTupleToKafkaMapper("key", "message"));
  withProducerProperties(properties);
}
 

import org.apache.storm.kafka.bolt.mapper.FieldNameBasedTupleToKafkaMapper; //导入依赖的package包/类
protected KafkaBolt<String,String> getKafkaBolt() {
    Properties props = new Properties();
    props.put("bootstrap.servers", "localhost:6667");
    props.put("acks", "1");
    props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
    props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

    final KafkaBolt bolt = new KafkaBolt()
            .withProducerProperties(props)
            .withTopicSelector(new DefaultTopicSelector(RESULT_TOPIC))
            .withTupleToKafkaMapper(new FieldNameBasedTupleToKafkaMapper<>());
    return bolt;
}
 

import org.apache.storm.kafka.bolt.mapper.FieldNameBasedTupleToKafkaMapper; //导入依赖的package包/类
/**
 * A topology that produces random sentences using {@link RandomSentenceSpout} and
 * publishes the sentences using a KafkaBolt to kafka "test" topic.
 *
 * @return the storm topology
 */
public StormTopology buildProducerTopology(Properties prop) {
    TopologyBuilder builder = new TopologyBuilder();
    builder.setSpout("spout", new RandomSentenceSpout(), 2);
    /**
     * The output field of the RandomSentenceSpout ("word") is provided as the boltMessageField
     * so that this gets written out as the message in the kafka topic.
     */
    KafkaBolt bolt = new KafkaBolt().withProducerProperties(prop)
            .withTopicSelector(new DefaultTopicSelector("test"))
            .withTupleToKafkaMapper(new FieldNameBasedTupleToKafkaMapper("key", "word"));
    builder.setBolt("forwardToKafka", bolt, 1).shuffleGrouping("spout");
    return builder.createTopology();
}
 

import org.apache.storm.kafka.bolt.mapper.FieldNameBasedTupleToKafkaMapper; //导入依赖的package包/类
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
  declarer.declare(new Fields(FieldNameBasedTupleToKafkaMapper.BOLT_KEY,
          FieldNameBasedTupleToKafkaMapper.BOLT_MESSAGE));
}